Notice that you did not get much response from this thread. My last trip there was 4-5 years ago and that was pre-Chowhound era, so I did not bother to keep name cards and details with me. Which is why I did not want to reply earlier as I was worried of giving outdated information.

Unfortunately, if you really want to try authentic Balinese food, both Kuta and Ubud are not really the place to go to. Both are touristy, and cater more for the tourists rather than the locals. If you are really eager to go for Balinese food, then it is best to go to Denpasar instead. But Denpasar is 1 hour drive from both Kuta and Ubud, so I don't think it is a good idea just to go there for food. Also you have to beware of the hygiene standard if you want to try street food.

Having said that, there is a restaurant in Nusa Dua that provides a comfortable environment for Balinese street food to tourists. You may want to check out Bumbu Bali : http://www.balifoods.com/bumbu/In Kuta, you may want to try Made's Warung for the nasi goreng or nasi campur. It is quite a hangout place for many in that area. At night, you may also want to try the seafood stalls at Jimbaran Beach, where rows of restaurants have opened alongside the sandy beach. But being a tourist, you are likely to be charged more than the locals.There is a trendy restaurant by the beach in Seminyak called Ku De Ta, serving contemporary food (like California cuisine by Australian chef, I believed). The atmosphere is really cool but it is not local food.

Thanks FourSeasons, we'll only be in Ubud for a day and the Kuta in question is on the island of Lombok (not the touristy Kuta in Bali). I'm pretty sure while on Lombok most of our meals will be authentic Indonesian. I've heard the places we'll be staying are not common tourist traps, we'll see.

I hope to eat in Denpasar at the end of the trip, but the first night we get in late so we'll head straight to Ubud.

Just one more note, Indonesian food is defined more by its provinces than its national identity. In Indonesia, there is really no such thing as Indonesian food, it is more like Padang food (from Padang), Sundar food (from West Jawa) etc etc.

posting Late, but for others: most of the street food is quite good. I did not partake, but for those inclined, you will find "Magic" Mushroom Tea Stalls on Trawangan and in other areas (certainly not the norm in NY :). Go Spicy or Go Home. The outdoor markets off the beaten path are for the adventurous...I popped a pepto pill every day to keep reasonably hydrated...I remember meats lying out in the sun...literally teeming with flies...but that is what the restaurants will end up serving you anyway if you are way off the Beaten Path. Ubud and Kuta you can get anything you want. Frankly, avoid Kuta all together...Ubud, though Touristy is special...but the food is not. Good luck!